Various methods and apparatus have been proposed for recycling asphaltic concrete in an elongated drum of a drum dryer type. Such apparatus and processes have been disclosed, for example, in my U.S. Pat. Nos. 4,177,080 and 4,215,941. In those inventions, virgin aggregate is introduced at one end of the drum and directly exposed to flame and hot gases of combustion from a burner at that same end, while downstream, used asphaltic concrete particles are introduced in an intermediate section of the drum between the burner and the opposite output end at which product is recovered. The aggregate is heated in the first portion of the drum adjacent the burner and is then mixed with the asphaltic concrete in the second portion of the drum adjacent the opposite output end, where the mixture of the heated aggregate and asphaltic concrete are recovered.
In the present invention, an elongated dryer drum type apparatus is provided with means for supplying composition intermediate the two opposite drum ends, but is also provided with a means for recovering composition intermediate the drum ends. Because of the structure of the apparatus, and the method in which it is used, there is provision for substantially heating and super-heating the virgin aggregate in the drum without danger of burning asphaltic concrete, which is heated in a section of the drum upstream away from the end into which flame and hot gases of combustion are introduced. Accordingly, the apparatus and method of the present invention offer a further alternative of recycling asphaltic concrete from those known heretofore.